2.4 Enzymes derived by recombinant technology
Applications of gene technology for the production of processing
aids are mainly focused on the use of recombinantly expressed
enzymes (Braunschweiger and Conzelmann, 1997). The regulations
on enzymes, including those produced by genetic engineering, are
not standardised in Europe. The EC directive 90/220/EEC applies
only to the release of GMOs, or to products containing GMOs, and
therefore does not concern enzymes deriving from recombinant technology.
Nor it is likely that the planned novel food legislation of the
EC will include enzymes. The Netherlands is one of the few countries
providing a complete list of enzymes (or other processing aids
and food additives) used in the food industry
(Approved 'Novel Food Products' in the Netherlands).
In Switzerland and the UK, several enzymes have also been listed
(Genetically engineered products approved for food use in the United Kingdom and
Approved genetically engineered food products in Switzerland),
whereas no such lists
were available from most of the other countries. Regulations on
enzymes, if present at all, vary greatly among different countries.
In Germany, the use of enzymes (and microorganisms) in food does
not generally require specific approval according to the LMBG
('Lebensmittel- und Bedarfsgegenständegesetz'). For certain
applications of enzymes, such as in cheese production, specific
registrations may be required; the German regulation for the manufacture
of cheese discriminates between natural rennet and its substitutes
(e.g. chymosin), requiring approval for the latter.
For the reasons given above, data on the approval of enzymes or
other processing aids or food additives derived by genetically
modified microorganisms has not been systematically summarised
here. Approved enzymes are listed only for the Netherlands, Switzerland
and the United Kingdom. The use of chymosin, expressed either
in Kluyveromyces lactis, E. coli K12 or Aspergillus
niger ssp. awamori, reportedly has been approved until
1993 in at least 17 countries, including Belgium, Chile, Denmark,
Finland, Hungary, Ireland, Israel, New Zealand, Norway, Poland,
Portugal, South Africa, Sweden, Switzerland, the United Kingdom,
the United States, and in the former Yugoslavia (Teuber, 1993).
In contrast to the regulatory situation, the picture of commercial
availability of recombinantly expressed enzymes is much clearer.
At least 19 different enzymes, most of which can be applied in
the food industry, have been produced by heterologous expression
in various genetically modified microorganisms
(Commercially available enzymes derived from recombinant technology).
In addition, some food additives are also produced by means of
genetically engineered microorganisms. Vitamin B12 manufactured
from Rhône-Poulenc has been recently approved for food use
in Switzerland (Approved genetically engineered food products in Switzerland),
apparently using genetically modified Agrobacterium radiobacter
(Braunschweiger and Conzelmann, 1997). Efforts to produce Vitamin B2
(riboflavin) using a recombinant Bacillus subtilis strain have also
been reported (van Loon et al., 1996). Very recently (on 17 February,
1997), riboflavin from Hoffmann-La Roche has been granted food
approval by the British Ministry of Agriculture, Fisheries and
Food (Genetically engineered products approved for food use in the United Kingdom).